This invention relates generally to inflatable restraint systems and, more particularly, to an apparatus and method for inflating an inflatable device such as an inflatable vehicle occupant restraint airbag cushion, such as commonly used in such systems.
It is well known to protect a vehicle occupant using a cushion or bag, e.g., an "airbag," that is inflated or expanded with gas when the vehicle encounters sudden deceleration, such as in a collision. In such systems, the airbag cushion is normally housed in an uninflated and folded condition to minimize space requirements. Upon actuation of the system, the cushion begins being inflated in a matter of no more than a few milliseconds with gas produced or supplied by a device commonly referred to as "inflator."
Many types of inflator devices have been disclosed in the art for inflating an inflatable restraint systems airbag cushion. Prior art inflator devices include compressed stored gas inflators, pyrotechnic inflators and hybrid inflators. Unfortunately, each of these types of inflator devices has been subject to certain disadvantages such as greater than desired weight and space requirements, production of undesired or non-preferred combustion products in greater than desired amounts, and production or emission of gases at a greater than desired temperature, for example.
In view ofthese and other related or similar problems and shortcomings of prior inflator devices, a new type an inflator, called a "fluid fueled inflator," has been developed. Such inflators are the subject of commonly assigned Smith et al., U.S. Pat. No. 5,470,104, issued Nov. 28, 1995; Rink, U.S. Pat. No. 5,494,312, issued Feb. 27, 1996; and Rink et al., U.S. Pat. No. 5,531,473, issued Jul. 2, 1996, the disclosures of which are fully incorporated herein by reference.
Such an inflator device utilizes a fuel material in the form of a fluid, e.g., in the form of a gas, liquid, finely divided solid, or one or more combinations thereof, in the formation of an inflation gas for an associated inflatable device. In one such inflator device, the fluid fuel material is burned to produce gas which contacts a quantity of stored pressurized gas to produce inflation gas for use in inflating a respective inflatable device.
While such fluid fueled inflators avoid or minimize at least some of the above-identified shortcomings of prior inflator devices, the proper storage of a fuel material together with a corresponding oxidant can be difficult, especially over prolonged periods of time such as are commonly or typically associated with inflatable restraint systems in automotive vehicles, which systems require a responsive lifetime which extends for a period of years. Also, while the separate storage of the fuel and oxidant can alleviate or reduce some such storage concerns, the complexity and cost of the design and manufacture of an inflator providing such separate storage of fuel and oxidant can be greater than desired.
In view thereof, there remains a need for an inflator device which satisfies one or more of the following objectives: increased simplicity of design and construction; avoidance or minimization of the risks or problems associated with the storing, handling and dispensing of various and selected gas generant materials; and permits even further reductions in assembly weight and cost.